Automatic heat control for carburetors



April 23, 1935.

D. FIRTH 1,998,497

AUTOMATIC HEAT CONTROL FOR CARBURETORS 3 Sheets-Sheet 1 Filed Aug. 22,1932 PQWMFZF??? April 23, 1935. D. FIRTH 1,998,497

AUTOMATIC HEAT CONTROL FOR CARBURETORS Filed Aug. 22, 1932 3Sheets-Sheet 2 a g 21 zz ll l April 23, 1935.

D. FIRTH 1 1,998,497

AUTOMATIC I-fEAT CONTROL FOR CARBURETORS v 3 Sheets-Sheet 3 Filed Aug.22, 1932 Patented Apr. 23, 1935 PATENT OFFICE AUTOMATIC HEAT CONTROL FORCARBURETORS David Firth, Flint, Mich, assignor to Marvel CarburetorCompany, Flint, Mich, a corporation of Illinois Application August 22,1932, Serial No. 629,855

11 Claims.

This invention relates to an improved thermostatic heat control for theinduction system of internal combustion engines and has specialreference to an automatic control of the heat supplied to the inductionsystem, modified by the power demand on the engine.

It is an object of this invention to provide an improved and simplifiedthermostatic heat control adapted to automatically compensate forvariations in the available heat supply and to modify the controllingtemperature of the induction system in response to variations in thepower demand on the engine. A variable temperature in the inductionsystem is highly desirable since smoothness of operation at light loadsor idling requires a maximum heating of the induction system at a timewhen the heating fluid available is at a lower temperature and smallvolume of flow while for maximum engine output the heating eifect shouldbe at a minimum while the heating fluid is then available at a hightemperature and greatly increased volume and pressure. I accomplishthese objects by providing an unbalanced valve controlling the diversionof exhaust gases for heating the induction system and controlling thisvalve by a spring type of thermostat, varying the spring tension bymeans of a throttle control, since the throttle position affords aconvenient index of the power demands on the engine; and hence of thedesirable heating effect required for best results in the induc tionsystem.

It is another object of this invention to provide an improved heatcontrol system for the intake manifold of an internal combustion enginecomprising an unbalanced diversion valve so mounted in the exhaustmanifold as to divert the exhaust gases into a heating jacket on theintake manifold and arranged to be moved from its diverting position bythe pressure of exhaust gases thereon, this movement being variablyresisted by cooperating thermostatic and throttle controls whichnormally impose sufiicient resistance against valve opening to assure avariable heating effect on the intake manifold which is at a maximumunder idling conditions 'with a cold engine.

Other and further important objects of this invention will be apparentfrom the disclosures in broken away, of the exhaust and inductionsystems of an internal combustion engine embodying the features of thisinvention.

Figure 2 is a section, partly in elevation; taken on the line II-II ofFig. 1 showing the exhaust 5 diversion valve and the heating jacket forthe induction system.

Figure 3 is an end view from the right side of Fig. 1 with thethermostat cover removed;

Figure 4 is a section on the line IV--IV of Fig. 2;

Figure 5 is a fragmentary view of the lift side of Fig. 1; and.

Figure 6 is a fragmentary elevation of an internal combustion engine andits carburetion and manifolding systems, showing an embodiment of thisinvention therein.

As shown:

The heating system of this invention has been illustrated in connectionwith a dual type of intake manifold it having separate passages llfeeding groups of cylinders in an engine block 8 through branches, oneof which is shown at B2 in Fig. 2. It is common practice to have a rowof alternating exhaust and intake port connections, one exhaustconnecting flange being shown at it which feeds into an exhaust manifoldM conveniently located beneath the various intake manifold branches l2.An exhaust outlet passage l5 leads downwardly from the manifold it andcontains a diversion valve chamber it formed as a cylinder transverselydisposed in the passage and open at the front for insertion of adiversion valve ill, to be later described. Below the valve chamber, theexhaust passage terminates in a mounting flange ill for the attachmentof the usual exhaust pipe.

The intake manifold i0 is fed by a riser casting l9 located between themanifold and a carbu-' retor 9, the riser forming a heating jacket abouttubes 20 which form riser passages from the carburetor to the manifoldl0, twin throttle valves 2! on a common shaft 22 being located at thelower end of the riser. The use of relatively thin tubes 20 inserted inthe heating jacket casting facilitates heat transfer to the mixtureflowing therethrough and is therefore my preferred construction,although it will be understood that such a construction is not essentialto this invention. Also, while my invention is 11- lustrated inconnection with a dual type of intake manifold, it will be evident thatit is equally applicable to a single type since my invention relates tothe control of the heat supply to the heating jacket l9.

The valve chamber "5 is connected by a pasrequirements.

sage 23 to the heating jacket IS, the exhaust gas flowing up around thetubes 26 and over a bafile 24 therebetween, thence through the lowerpart of the jacket beneath a baille 25 to an outlet passage 26 openinginto the valve chamber below the first. passage 23.

The unbalanced diversion or damper valve if is mounted on a shaft 28journaled in offset relationship to the axis of the valve chamber oneend of the shaft extending through the rear wall 26 of the chamber whilethe front end extends through a cover or cap 36 closing the front of thechamber. The overhanging edge of the Valve cooperates with a land 3! onthe chamber wall to cause a deflection of the exhaust gases into thepassage 23 while the narrow side of the valve cooperates with a land 32between the two passages 23 and 26, the valve opening in ananticlockwise direction in Figure 2 in response to exhaust pressure.During the opening movement the narrow side of the valve approaches aland 33 above the passage 23 but this land may be purposely cut back apredetermined amount to allow a certain amount of exhaust gas flow tothe heating jacket even with the valve open.

The front end of the shaft 261s slotted at 34 to receive one end of acoiled bimetallic thermostatic member 35 the other end of which ishooked to a pin 36 carried by a lever 31 pivoted on the shaft 28. Onreferring to Figure 3 it will be evident that a counter-clockwisemovement of the lever 31 and pin 36 will unwind or loosen the thermostat35 to in effect decrease the tension thereof and tend to rotate thevalve shaft likewise or in a direction to cause the counter clockwiseopening of the valve in response to exhaust pressure thereon. Thus theeffect would be to decrease the temperature required to unwind thethermostat and thus assist the valve to opening readily when the desiredtemperature is reached.

While the lever 31 could be placed under the control of the operatorindependently of other controls, I prefer to coordinate the levermovements with the operation of the throttle valves 2i since much moreheat is desirable under idling conditions than when operating the'engineunder load. Since the throttle controls the engine it is thus convenientto derive the thermostat control from the throttle, although varioustypes of engines may require different stages of temperature variationsbetween theidling and power The throttle control may conveniently betaken from a lever 38 carried by the throttle shaft 22, a link or rod 39connecting the lever 38 to a separate lever 40 pivoted to one side ofthe thermostat and having a cam like groove 4! therein engaging theanchor pin 36. Reference to Figure 3 will show that the first part ofthe groove v36 may be arranged as of constant radius relative to thelever pivot, the subsequent part of the groove being of increasingradius so that as the throttle is opened the lever 40 swingscounterclockwise in Figure 3 eventually allowing the pin 36 to swing ina direction to release the tension in the coiled thermostat and thus ineffect reducing the temperature required to open I the diversion valve.

The valve I1 is not provided with an abutment defining its closed ordiverting position, but the projecting rear end of the shaft 23 has alever 42 applied thereto and engaged by a spring 43 which spring in itsnormal contracted position defines the desired valve diverting position.The valve may however swing past the normal position by stretching thespring '43 which is proportioned to yield before the thermostat issubjected to damaging strains. The lever 42 is provided with anelongated slot 44 into which one end of the spring is hooked, the

slot providing sufficient lost motion or play to permit normal openingmovement of the valve.

The thermostat is normally covered by a shield 45 mounted on spacerstuds 46 which allow a circulation of air under the edges of the shieldto modify the responsiveness of the thermostat to heat conducted alongthe valve shaft 23 and radiated from the valve chamber cover 36.

In the. operation of the heat control of my invention reference may behad to Figures 2 and 3 wherein the throttles are closed and thediversion valve 26 is turned to cause all exhaust gases to pass throughthe intake manifold heating jacket. The thermostat is then exerting themaximum amount of tension opposing an opening movement of the diversionvalve due to the exhaust pressure acting on the unbalanced area thereof.With the maximum heat supply thus assured quick warming up of the engineresults. As the exhaust pressure increases due to a speeding up of theengine it will tend to open or rotate the valve counterclockwise,allowing some of the gas to escape past the valve. This opening movementof the valve may even extend to the full open position, against theresistance of the thermostat, if the exhaust pressure increasessufiiciently. As the exhaust manifold warms up heat is transferred tothe thermostat decreasing the resistance thereof and in hot climates orunder heavy and continuous loads the thermostat may even open the valveindependently of exhaust pressure.

As the throttle is opened the anchor pin 36 is shifted in acounterclockwise direction as shown in Figure 3 and thus releases thetension of the thermostat, thus allowing the valve to open when only aminimum amount of exhaust pressure exists. For example if the driveropens the throttle wide to climb a hill before the thermostat has beenwarmed up enough to automatically release some of the cold tensiontherein, the throttle linkage operates to mechanically release thistension so that back pressure is cut down in the exhaust system byallowing the valve to open against less resistance.

It will thus be seen that I provide an unbalanced diversion valvenormally resiliently held in its diverting position and I vary theresistance opposing the opening of the valve in accordance with bothtemperature and operating demand conditions, the valve being opened bytemperature alone only under extreme conditions.

Although the present invention has been hereinabove described asembodying an unbalanced valve, a preferred form of the invention, itwill be understood by one skilled in the art that many mechanicalchanges may be made without departing from the spirit of the invention.For example, a balanced diversion valve may be used and, since abalanced valve would not be subject to an opening effect from exhaustgas pressure, the yielding stop might be eliminated; also, a direct orother type control of the effective temperature responsiveness of thethermostat might be employed, all in a manner deemed obvious from thedisclosures herein.

I am aware that'many changes may be made and numerous details ofconstruction may be varied through a wide range without departing fromthe principles of this invention, and I, therefore, do not purposelimiting the patent granted hereon otherwise than necessitated by theprior art.

I claim as my invention:

1. A manifolding system for internal combustion engines comprising anexhaust manifold and a throttle controlled intake manifold having aheating jacket adapted to be heated by gases from the exhaust manifold,a valve chamber in said exhaust manifold, ports opening into said valvechamber and in communication with the heating jacket of the intakemanifold, an unbalanced damper valve pivotally mounted in said valvechamber in such a way as to tend to open in response to exhaustpressure, said valve being adapted to normally yieldingly divert thefiow of exhaust gases from said exhaust manifold through one of theports to the heating jacket, a coiled thermostat operatively connectedto the unbalanced valve to yieldingly maintain said valve in said normalposition in opposition to the pressure of the exhaust gases thereon andmeans connected to the throttle to vary the tension of said coiledthermostat whereby to vary the resistance opposing the opening of thevalve to reduce the normal temperature in the heating jacket as thethrottle is moved towards the open position.

2. A manifolding system for internal combustion engines comprising anexhaust manifold and an intake manifold having a heating jacket adaptedto be heated by gases from the exhaust manifold, a valve chamber in saidexhaust manifold, ports opening into said valve chamber and incommunication with the heating jacket ofthe intake manifold, anunbalanced damper valve pivotally mounted in said valve chamber in sucha way as to tend to open in response to exhaust pressure, said valvebeing adapted to normally yieldingly divert the flow of exhaust gasesfrom said exhaust manifold through one of theports to the heatingjacket, a coiled thermostat operatively connected to the unbalancedvalve to yieldingly maintain said valve in said normal position inopposition to the pressure of the exhaust gases thereon and means tovary the tension of said coiled thermostat whereby to vary theresistance opposing. the opening of the valve.

3. A manifolding system for internal combustion engines comprising anexhaust manifold and a throttle controlled intake manifold having aheating jacket adapted to be heated by gases from the exhaust manifold,a valve chamber in said exhaust manifold, ports opening into said valvechamber and in communication with the heating jacket of the manifold, anunbalanced diversion valve so mounted in said valve chamber as to tendto open from a normal position obstructing the exhaust manifold inresponse to" increased exhaust gas pressure, thermostatic means normallyopposing the opening movement of said diversion valve and adapted toincreasingly yield to said opening movement as the temperatureincreases, and means for varying the opposing force of said thermostaticmeans in response to engine operating conditions.

4. A manifolding system for internal combustion engines comprising anexhaust manifold and a throttle controlled intake manifold having aheating jacket adapted to be heated by gases from the exhaust manifold,a valve chamber in said exhaust manifold, ports opening into said valvechamber and in communication with the heating jacket of the manifold, anunbalanced diversion valve so mounted in said valve chamber as to tendto open from a. normal position obstructing the exhaust manifold inresponse to increased exhaust gas pressure, thermostatic means normallyopposing the opening movement of said diversion valve and adapted toincreasingly yield to said opening movement as the temperatureincreases, and throttle operated means adapted to increase the opposingpressure of said thermostatic means as the throttle moves toward itsidling position.

5. A heat control system for the intake manifold of an internalcombustion engine, comprising a heatingjacket associated with the intakemanifold, an exhaust manifold connection to the heating jacket, anunbalanced valve adapted in one position to divert exhaust gases to theheating jacket, said valve being so arranged as to be shifted from itsdiverting position by exhaust gas pressure thereon, a coiled bimetallicthermostat operatively connected at one end to said valve to variablyoppose said shifting movement, a movable anchor for the other end ofsaid thermostat and means for moving said thermostat anchor in step withthe power requirements of the engine to vary the temperatureresponsivenessof said thermostat.

6. A heat control system for the intake manifold of an internalcombustion engine, comprising a heating jacket associated with theintake manifold, an exhaust manifold connection to the heating jacket,an unbalanced valve adapted in one position to divert exhaust gases tothe heating jacket, said valve being so arranged as to be shifted fromits diverting position by exhaust gas pressure thereon, a thermostatoperatively connected to said valve to variably oppose said shiftingmovement, a movable anchor for said thermostat and throttle operatedmeans adapted to shift said thermostat anchor to vary the thermostaticcontrol in predetermined relationship to the movement of the throttle.

7 A heat control system for the intake manifold of an internalcombustioniengine, comprising a heating jacket associated with theintake manifold, an exhaust manifold connection to the heating jacket,an unbalanced valve adapted in oneposition to divert exhaust gases tothe heating jacket, said valve being so arranged as to be shifted fromits diverting position by exhaust gas pressure thereon, a coiledbimetallic thermostat operatively connected at one end to said valve tovariably oppose said shifting movement, a movable anchor for the otherend of said thermostat, and throttle operated means adapted to shiftsaid thermostat anchor to vary the thermostat control in predeterminedrelationship to the movement of the throttle.

8. A heat control for the manifolding system of an internal combustionengine having an intake and an exhaust manifold including, a heatingjacket associated with the intakemanifold, means establishingcommunication between the exhaust manifold and said jacket, valve meanscontrolling the diversion of exhaust gases from the exhaust manifold tosaid jacket, said valve means comprising an unbalanced valve positionedin said exhaust manifold and transversely to the flow of exhaust gasesand pivotally mounted to be swung by the force of exhaust gases from aclosed position transversely of the exhaust manifold, wherein exhaustgases are by-passed through the jacket, to an open position, wherein iiithe gases are free to exhaust without passing through the jacket,thermostatic means responsive to exhaust temperatures eifectingexclusive direct control over said valve means and opposing swinging ofsaid valve by exhaust gases, and

means varying the responsiveness of said thermostatic means to exhausttemperatures to decrease the temperature at which the exhaust gasesovercome the thermostatic means when the throtthe exhaust manifold andsaid jacket, valve means controlling the diversion of exhaust gases fromthe exhaust manifold to said jacket, thermostatic means responsive toexhaust temperatures efiecting a control over said valve means, andmeans reducing the exhaust temperature to which said thermostatic meansis responsive to decrease the'diversion of exhaust gases to said jacketin accordance with the degree of throttle opening.

10. A heat control for the manifolding system of an internal combustionengine including a heating jacket associated with the intake manifold,means establishing communication between the exhaust manifold and saidjacket, valve means controlling the diversion of exhaust gases from theexhaust manifold to said jacket, thermostatic means effecting exclusivedirect control over said valve means, and throttle operated meansexercising a control over the efiective temperature responsiveness ofsaid thermostatic means.

11. A heat control for the manifolding system of an internal combustionengine including a heating jacket associated with the intake manifold,means establishing communication between the exhaust manifold and saidjacket, valve means controlling the diversion of exhaust gases from theexhaust manifold to said jacket, thermostatic means responsive toexhaust temperatures efieeting exclusive direct control over said valvemeans, and throttle operated means varying the responsiveness of saidthermostatic means to exhaust temperatures.

DAVID FIRTH.

